This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Parkinson's Disease-PD affects more than 1.5 million people in the United States alone;its prevalence increases with age, and the majority of the diagnoses occur over age 60. While PD is primarily associated with motor symptoms such as resting tremor and rigidity, it is also associated with debilitating cognitive symptoms. Little is known about whiter matter and cognition in PD despite growing research suggesting pathological changes in the white matter may contribute to the degenerative disease. The present investigation will determine: the contribution of white matter integrity on the processing speed and working memory deficits of idiopathic PD. n=45, relative to that of an age and education matched control group, n=45, and the predictive role of white matter on cognitive change after one year. This project will contribute much needed knowledge about the role of white matter integrity on cognitive function in PD. The information will contribute to our ability to predict cognitive change in PD thereby improving treatment decisions and intervention options for PD.